Temperature sensors are commonly mounted at various locations in automobiles and other vehicles to monitor operating conditions within the vehicle. A high temperature can indicate that a particular component is not working properly or is about to fail.
One common location for a temperature sensor in a vehicle is connected or adjacent to a starter motor or other vehicle electric machine. For example, a temperature sensor in the form of a thermal switch, also known as a thermal cutoff or thermal link, may be positioned in the circuit that delivers power to the starter motor. When the thermal switch is heated to a predetermined temperature, the thermal switch interrupts electrical current to the starter motor.
Thermal switches may be mounted in any of various locations near the starter motor housing. One common mounting location is on the brush plate for the starter motor. An exemplary prior art mount for a thermal switch on a starter motor base plate is shown in FIG. 5. The mount includes a metallic mounting bracket 210 that is fastened to a base plate 200 of the starter motor, which may be, for example, the brush holder plate. The mounting bracket 210 includes a central plate portion that provides a retention surface 212, two sidewalls 214 extending from the retention surface 212, and two ears 216 extending outward from the sidewalls 214, parallel with the retention surface 212. Each ear includes an opening 218 that is aligned with a hole extending through the base plate 200. Fasteners 220, such as rivets or bolts, extend through the openings 218 and the holes in the base plate 200 to secure the mounting bracket 210 to the base plate 200. A thermal switch 202 is positioned between the base plate 200 and the retention surface 212 of the mounting bracket. The thermal switch 202 includes leads 204 that extend outward past an outer perimeter of the base plate. One lead is welded to the base plate 200. The other lead is connected to a coupler 206 that leads to an external magnetic switch (not shown).
While the arrangement of FIG. 5 is adequate for mounting a thermal switch to a brush holder plate, various aspects of the arrangement could be improved upon. For example, in the arrangement of FIG. 5 a relatively large area is required on the base plate for the mounting members, including the ears 216 and the fasteners 220. Additionally, the arrangement of FIG. 5 generally limits the options for orienting the sensor on the base plate.
In view of the foregoing, it would be advantageous to improve upon the mounting arrangement. For example, it would be advantageous for such mounting arrangement to be provided using fewer components and less expensive components. It would also be advantageous if such mounting arrangement could be provided using less space on the base plate. Moreover, it would be advantageous to provide a mounting arrangement that provides the manufacturer with the ability to orient the thermal sensor in a way such that wires from the sensor are contained within the confines of the base plate and without protruding outside of the inner diameter or outer diameter of the base plate. Additionally, it would be advantageous if assembly of the mounting arrangement could be simplified, requiring fewer assembly steps, thus simplifying the manufacturing process and saving on manufacturing costs.